RESEARCH PROGRESS: 1. Research on Herpes Simplex Virus Type 2 Carcinogenesis: 1. Studies on Special Viral Antigen AG-4; 2. Investigation of the Lytic Function and Neoplastic Transformation of the Herpes-virus by a Cloning System of Syriam Hamster Embryonic Fibroblast; 3. Investigation of the Interaction of the Herpesvirus DNA with the Host Cells. 2. Mechanism of In Vitro Neoplastic Transformation: 1. Improvement on Techniques for the Study of In Vitro Neoplastic Transformation; 2. Establishment of the Syrian Hamster Embryonic Cell System for the Concomitant Studies of Neoplastic Transformation and Somatic Mutation. 3. Research on Diethylnitrosamine (DEN) Hepatocarcinogenesis; 4. Changes in DNA Sequence Organization and Gene Expression in Neoplastic Transformation; 5. Demonstration of a Direct Involvement of DNA Damage in Neoplastic Transformation.